|Depleted uranium aperture bar.|
William Kolb is the co-author of a wonderfully interesting book about radioactivity in our lives, which anyone interested in collecting radioactive objects, or just interested in radioactivity in general, should definitely buy without delay. (Click the link to find out how to order it.)
Using his book I have been able to identify and more accurately describe quite a few objects pictured on this website (mostly under uranium and radium). In fact, I found pictures of many of the exact things I'd already collected!
This particular bar I actually saw in the book before I got one, and when I saw the picture I thought, ah, wouldn't it be great to have a bar like that: Too bad there's no chance of that ever happening. I'd already scoured the one abandoned hospital I had access to without finding any misplaced Cobalt-60 sources, any depleted uranium shipping containers, nor any radon needles. All I found was a lousy polonium anti-static brush and a couple of tons of lead (not that I'm complaining or anything, the lead is great.)
Then right after Christmas, what should I find on my desk but a box with this fabulous bar in it! Elements seem to go in bursts: After nearly a year with no pure uranium, I ended up with two large pieces, totaling well over two pounds, in the span of just a couple of days.
To quote from the picture caption in William's book (page 128):
A curved bar of depleted uranium from a teletherapy unit. Four such bars formed an aperture that could be opened and closed to illuminate a rectangular area over the part of the body to be exposed. Surface activity on the bar was about 250,000 counts per minute but dropped to 8,000 at 12 inches, or roughly 2 mR/h (Ca 1960s to 1980s)As with any depleted uranium object, the first thing you notice is the weight. Though slightly less dense than pure uranium (about 17g/cc vs. 19g/cc), it's still very surprisingly heavy and wonderful to hold.
As with the cylinder above, the donor wishes to remain anonymous so as not to be known as someone who has this very rare substance available.
Acquired: 27 December, 2002
Text Updated: 29 January, 2009